Testing for Consistency in Tourists' Willingness to Pay for New Nature Reserves in the Gulf of Morbihan (France)

In this paper, we develop an empirical test of consistency in contingent willingness to pay (WTP) responses, which is based on the following a priori expectation. In economics, when an individual considers paying for public goods, his decision to pay, and his WTP are based on utility-maximising behaviour. Accordingly, supposing other factors are identical, if individual A expresses greater interest in paying for public goods in general than individual B, that is because A receives more benefits from the use and/or the non-use of these goods than B. Continuing with this logic, if both individuals are asked about their WTP for a precise public good, A should logically be more likely to pay and should be willing to pay more than B. Thus, the test consists in measuring the degree to which people are likely to give money for public goods in general, and including it as a covariate in WTP models for the specific public good. If this covariate is significantly positive, then WTP responses are considered consistent. If this is not the case, then future research might focus on motives behind inconsistent WTP responses. To assess the robustness of the test, we consider 3 situations 1) the covariate is exogenous 2) it is endogenous and uncorrelated with the choice to pay or not for the specific good 3) it is endogenous and correlated with this choice. Using a contingent valuation study estimating tourists’ willingness to pay for future nature reserves in the Gulf of Morbihan, we find that WTP responses are consistent in all situations considered.contingent valuation, consistency, endogeneity, Consumer/Household Economics, Resource /Energy Economics and Policy, C24, D12, Q26,

Comparison of two extraction methods for ergosterol determination in vegetal feeds

Ergosterol is the principal sterol of fungi in which it plays an essential role in cell membrane and other cellular constituents. This sterol is considered as a good marker of fungal contamination and of mycotoxin production. After validation of ergosterol quantification by HPLC-UV system (linearity range: 0.2 to 20.0 mg/ml, repeatability: 3.27%, between day precision: 4.75%), 2 extraction methods of ergosterol from 3 vegetal matrixes (maize, barley and wheat) were compared: the first one, normalized by the AFNOR, is based on solid phase extraction (SPE), while the other is based on liquid/liquid extraction (LLE). The LLE procedure allowed ergosterol extraction gains of around 20% for high initial sterol contents (3 to 5 mg/kg) in naturally contaminated matrixes or in spiked samples, and of 86% for low initial sterol contents (1-2 mg/kg) in maize. Moreover, the precision of ergosterol determination was comparable for the 2 methods even if it was slightly lower using LLE and was more affected by the initial ergosterol contents in vegetal matrix than by its nature. These results suggest that ergosterol contents in vegetal feeds would be underestimated with the official method (SPE) and emphasize the importance of the extraction step

Production and purification of fumonisins from a highly toxigenic Fusarium verticilloides strain

Fumonisins are the major mycotoxins produced by Fusarium verticilloides and F. proliferatum fungi which are widely found as contaminants in corn and corn screenings. These molecules are hepatotoxic and nephrotoxic for several species and carcinogenic in rodents. Moreover their consumption was linked to high prevalence of human oesophageal cancer in certain geographic areas. The aim of this work was to improve FB1 production and purification procedures in laboratory conditions in order to produce large quantities of semi-purified toxin that may be used in experimental intoxications of farm animals. We used a highly toxigenic strain of Fusarium verticilloides (NRRL-3428) isolated from feeds. Influence of substrate, temperature, water content, culture recipient size and screen analysis of the substrate on fumonisin production was tested. Optimal production was obtained when strain was grown on coarsely cracked corn with 50% water content at 21°C during 5 weeks. This allowed the production of 3 to 4 g of fumonisin B1 per kg of culture material. The composition of the extracts was found to be as follow : 54% FB1, 8% FB2, 9% FB3 and 29% of pigments coming from corn. The ratio observed between FB1 and FB2 is comparable to the one reported in naturally contaminated corn. Further purification of these extracts on SAX columns led to the removal of pigments and to obtain of fumonisins extracts pure enough to be used for intra-venous or intra-peritoneal injection

Toxicokinetics of fumonisin B1 in turkey poults and tissue persistence after exposure to a diet containing the maximum European tolerance for fumonisins in avian feeds

The kinetic of fumonisin B1 (FB1) after a single IV and oral dose, and FB1 persistence in tissue were investigated in turkey poults by HPLC after purification of samples on columns. After IV administration (single-dose: 10 mg FB1/kg bw), serum concentration–time curves were best described by a three-compartment open model. Elimination half-life and mean residence time of FB1 were 85 and 52 min, respectively. After oral administration (single-dose: 100 mg FB1/kg bw) bioavailability was 3.2%; elimination half-life and mean residence time were 214 and 408 min, respectively. Clearance of FB1 was 7.6 and 7.5 ml/min/kg for IV and oral administration respectively. Twenty four hours after the administration of FB1 by the intravenous route, liver and kidney contained the highest levels of FB1 in tissues, level in muscle was low or below the limit of detection (LD, 13 µg/kg). The persistence of FB1 in tissue was also studied after administration for nine weeks of a feed that contained 5, 10 and 20 mg FB1+FB2/kg diet. Eight hours after the last intake of 20 mg FB1+FB2/kg feed (maximum recommended concentration of fumonisins established by the EU for avian feed), hepatic and renal FB1 concentrations were 119 and 22 µg/kg, level in muscles was below the LD

Effet d’une taxe et d’un droit d’entrée sur les consentements à payer des touristes pour de nouvelles réserves naturelles dans le golfe du Morbihan

(article en français) Using contingent valuation method, this paper empirically examines the effects of a special accommodation tax and an entrance fee on tourists’ willingness-to-pay (WTP) for new nature reserves in the Gulf of Morbihan (France). The results show that the payment vehicles affect not only the decision to pay, but also the amounts given. Beyond this significant impact, they demonstrate that tourists receive a benefit from the creation of nature reserves.contingent valuation method, nature reserve, payment vehicle, accommodation tax, entrance fee, tourist

Deciphering the Anti-Aflatoxinogenic Properties of Eugenol Using a Large-Scale q-PCR Approach

Produced by several species of Aspergillus, Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin contaminating many crops worldwide. The utilization of fungicides is currently one of the most common methods; nevertheless, their use is not environmentally or economically sound. Thus, the use of natural compounds able to block aflatoxinogenesis could represent an alternative strategy to limit food and feed contamination. For instance, eugenol, a 4-allyl-2-methoxyphenol present in many essential oils, has been identified as an anti-aflatoxin molecule. However, its precise mechanism of action has yet to be clarified. The production of AFB1 is associated with the expression of a 70 kB cluster, and not less than 21 enzymatic reactions are necessary for its production. Based on former empirical data, a molecular tool composed of 60 genes targeting 27 genes of aflatoxin B1 cluster and 33 genes encoding the main regulatory factors potentially involved in its production, was developed. We showed that AFB1 inhibition in Aspergillus flavus following eugenol addition at 0.5 mM in a Malt Extract Agar (MEA) medium resulted in a complete inhibition of the expression of all but one gene of the AFB1 biosynthesis cluster. This transcriptomic effect followed a down-regulation of the complex composed by the two internal regulatory factors, AflR and AflS. This phenomenon was also influenced by an over-expression of veA and mtfA, two genes that are directly linked to AFB1 cluster regulation

Taxonomy based on science is necessary for global conservation

Peer reviewe

Acquisition des qualités organoleptiques de la viande bovine (adaptation à la demande du consommateur)

La qualité d'une viande peut se définir suivant quatre qualités organoleptiques majeures : la couleur, la jutosité, la flaveur et la tendreté. La connaissance actuelle de la transformation du muscle en viande permet aujourd'hui d'évaluer ces critères de qualité par des méthodes instrumentales mais aussi et surtout sensorielles. Chacune de ces qualités peut être modifiée, améliorée ou détériorée depuis la naissance de l'animal jusqu'à sa mort, que ce soit par la génétique, l'alimentation, la zootechnie, la technique d'abattage ou au final la cuisson du produit. Cependant ces différents paramètres interagissent entre eux et complexifient encore les relations étroites existant entre ces quatre qualités organoleptiques prédominantes. A terme, les techniques d'obtention des viandes conduisent à des appellations de qualité où signification réelle et image ne sont pas toujours évidentes à identifier.TOULOUSE-EN Vétérinaire (315552301) / SudocTOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

Epidémiologie des derniers épisodes de trichinellose humaine en France et conséquences réglementaires

TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE-EN Vétérinaire (315552301) / SudocSudocFranceF

Le fromage de chèvre (spécificités technologiques et économiques)

Le lait de chèvre est plus pauvre en matières utiles que le lait de vache. Son rendement fromager est donc plus faible. Ce sont les spécificités de sa composition en matières grasses qui donnent au fromage de chèvre son goût caractéristique. Il existe deux procédés de fabrication du fromage de chèvre. Le plus répandu utilise des bactéries lactiques pour faire coaguler le lait. C'est un procédé naturel lent qui donne un caillé friable et perméable. L'autre technique consiste à ajouter de la présure et on obtient assez rapidement un caillé ferme et imperméable. La France est le premier pays européen en terme de production laitière et fromagère. La collecte de lait ne cesse d'augmenter. Il faut s'attendre en revanche à un avenir plus incertain à cause des mesures prises dans la nouvelle politique agricole commune. Elles prévoient la baisse du prix d'achat du lait de vache, ce qui entraînera une baisse du prix du lait de chèvre de manière indirecte.TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE-EN Vétérinaire (315552301) / SudocSudocFranceF